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Multifunctional bio-electrocatalytic systems for reduction of oxygen and hydrogen peroxide

Barbara Kowalewska 1Krzysztof Miecznikowski 1Paweł J. Kulesza 1Anna Belcarz 2Grażyna Ginalska 2

1. Warsaw University, Faculty of Chemistry, Pasteura 1, Warszawa 02-093, Poland
2. Medical University, Faculty of Pharmacy, Department of Biochemistry, Chodźki 1, Lublin 20-093, Poland


    Combination of multi-walled carbon nanotubes, cobalt porphyrin, and peroxidase (horseradish, cabbage) enzyme in the film (deposited onto glassy carbon electrode substrate) produces a bio-electrocatalytic system capable of effective reduction of oxygen in such neutral media as 0.1 mol dm-3 KCl and 0.1 mol dm-3 KCl + 0.01 citrate buffer (pH = 6).
    Carbon nanotubes have been modified with ultra-thin layers of 4-(pyrrole-1-yl) benzoic acid, or phosphododecamolybdate, to form stable colloidal suspensions of carbon nanostructures. The resulting inks have been utilized during sequential deposition of components. Co-existence of cobalt porphyrin, peroxidase enzyme together with dispersed carbon nanotubes leads to synergistic effect that is evident from some positive shift of the oxygen reduction voltammetric potentials (more than 50 mV in citrate buffer) and significant (ca. twice) increase of voltammetric currents (relative to those of the enzyme-free system). The multi-component bio-electrocatalytic film has also exhibited relatively higher activity towards reduction of hydrogen peroxide. It is reasonable to expect that the reduction of oxygen is initiated at cobalt porphyrin redox centers, and the undesirable hydrogen peroxide intermediate is further reduced at the horseradish or cabbage peroxidase enzymatic sites. An important function of carbon nanotubes is to improve transport of electrons within the bio-electrocatalytic multi-component film.


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Related papers

Presentation: Poster at SMCBS'2007 International Workshop, by Barbara Kowalewska
See On-line Journal of SMCBS'2007 International Workshop

Submitted: 2007-09-07 14:42
Revised:   2009-06-07 00:44